肺炎支原体感染大鼠肺组织中PDGF-BB变化的免疫组织化学研究

为探讨血小板源性生长因子 - BB(PDGF- BB)在肺炎支原体反复肺感染导致肺间质纤维化的发病机制中的作用 ,作者于 2 4周内给大鼠反复 9次吸入肺炎支原体复制慢性肺感染模型。随后用 PDGF- BB单克隆抗体按 SABC法行免疫组织化学染色和定量图像分析 ,以观察肺组织 PDGF- BB蛋白质水平表达的变化。结果显示 :(1)感染组动物 (n=4)支气管肺泡灌洗液肺炎支原体 - PCR检测均为阳性 ,而对照组 (n=4)和感染加红霉素治疗组动物 (n=4)均为阴性 (P<0 .0 5 ) ;三组动物的支气管和肺组织常规细菌培养结果均为阴性 ;感染组动物透射电镜检查见肺泡间隔增宽 ,其中有较多胶原纤维堆积 ,其余两组则未见明显异常。 (2 )感染组动物肺间质结缔组织内、支气管壁和小血管壁内可见较强的 PDGF- BB阳性染色 ,其积分光密度为 37.90± 10 .14(n=4) ,显著高于对照组者 (7.5 4± 1.98,n=4,P<0 .0 5 )和感染加红霉素治疗组者 (10 .90± 3.30 ,n=4,P<0 .0 5 )。提示肺炎支原体反复肺感染的 PDGF- BB蛋白质水平表达增加 ,可能参与肺间质纤维化的发病过程

IMMUNOHISTOCHEMICAL RESEARCH ON THE CHANGES OF PDGF-BB IN LUNG TISSUE OF RATS INFECTED BY MYCOPLASMA PNEUMONIAE

In order to investigate the role of platelet derived growthfactor-BB(PDGF-BB) in the pathogenesis of pulmonary interstitial fibrosis in rats repeatedly infected by mycoplasma pneumoniae (MP), the authors established a chronic pulmonary infected rat model by indhaling MP for 9 times in 24 weeds. Then immunohistochemical stain was performed with PDGF-BB monoclonal antibody and the results were quantitatively analyzed to measure the changes in PDGF-BB protein expression in the lung tissue. The results showed: (1) MP polymerase chain reaction (PCR) test showed positive results in the bronchoalveolar lavage fluid (BALF) from all of the MP-infected rats (infectious group, n=4), while they were all negative in BALF from the control group (n=4,P＜0.05) and from those rats both infected with MP and, at the same time, treated with erythromycin (treating group n=4，P＜0.05). Bacterial cultures of the bronchial and lung tissue were negative in all three groups. Using transmission electron microscope the widened interalveolar septa with increased amount of collagen were found in the infectious group, while there were no obvious abnormalities in the other two groups. (2) Strong positive stain of PDGF-BB protein was found in the interstitial conncetive tissue, the bronchial wall and the wall of blood vessels in the lung tissue from the infectious group. The integral optical density was 37.90±10.14，which was significantly higher than the value of control group (7.54±1.98，P＜0.05) and the treating group (10.90±3.30，P＜0.05). These results suggest that PDGF-BB protein expression is increased in the lung tissue with MP-infection, which may by involved in the process of the pathogenesis of pulmonary interstitial fibrosis caused by repeated MP-infection.